A 19-year old Chinese man is in police custody after allegedly hacking into a provincial seismological bureau's website to place a false earthquake warning, state media have reported.

The teenager, identified only by his surname Chen, altered the website of the Guangxi Seismological Bureau to warn residents in southwestern China to prepare for an impending earthquake expected to measure 9.0 on the Richter scale, according to a report on China Central Television's website.

Such a posting could have caused a panic. On May 12 an earthquake measuring 7.8 struck China's Sichuan province, killing over 70,000 people and leaving millions homeless. Following the quake, many people have fallen prey to rumours that earthquakes can now be predicted in a manner similar to weather forecasts, although there was no warning of the Sichuan quake.

Authorities did not say what impact the hacker's posting had.

An earthquake measuring approximately 9.0 was the cause of the 2004 Asian tsunami, which killed about 250,000 around the Indian Ocean.

Chen was arrested in the Guangxi province city of Taicang on June 4, and was being held in the provincial capital of Nanning. The report did not indicate what the exact charges would be, nor when Chen might face trial or what type of punishment was possible if he is convicted.

Chen had confessed and said that he altered the website to demonstrate his technical skills, according to the report.